156818-7720 ZEXEL 9 423 610 997 BOSCH FLYWEIGHT ASSEMBLY 9423610997 1568187720 1686499515

Tachometer Drive
Use a short fiber grease, No. 2 Grade for most temperatures, or No. 0 or No. 1 for extremely low temperatures. Wipe surrounding area with a clean rag before removing plug. Remove plug. Install grease fitting. Apply two strokes of lubricant through the fitting. Remove grease fitting. Replace plug.Governor Control Cross Shaft Bearings (1673)
Engines Before 69D3625)
Use a short fiber grease No. 2 Grade for most temperatures, or No. 0 or No. 1 for extremely low temperatures. Apply 1 stroke of lubricant through fitting at each end of shaft.Valve Adjustment
1673C
Make valve adjustment with engine stopped and cold. Remove the flywheel timing cover and rotate flywheel in direction of engine rotation until "TC 1-6 cyl" mark aligns with timing pointer. Remove valve cover and observe position of valves to determine if No. 1 or No. 6 piston is on compression stroke. Both the inlet and exhaust valves will be closed on compression stroke.1. With No. 1 piston at TDC on compression, check lash on exhaust valves for cylinders 1, 3 and 5, and inlet valves for cylinders 1, 2 and 4.2. To adjust, loosen valve adjusting locknut and turn adjusting screw to allow feeler gauge to pass between top of valve stem and the valve rocker arm.3. Set lash at .015" (0.38 mm) for inlet and .025" (0.63 mm) for exhaust valves.4. Tighten adjusting screw locknut and check lash clearance.5. Turn flywheel 360° in direction of engine rotation. Align flywheel timing mark with pointer. No. 6 cylinder will be at TDC compression stroke (valves closed).6. Check lash on exhaust valves for cylinders 2, 4 and 6, and inlet valves for cylinders 3, 5 and 6. Adjust valves if necessary.1674
Make valve lash adjustment with engine stopped. TDC of the No. 1 piston on the compression stroke is the reference point. The No. 1 piston will be at TDC when the No. 1 and No. 6 flywheel timing mark aligns with the timing pointer. Compression stroke is when all the No. 1 piston valves are closed.1. With No. 1 piston at TDC compression stroke, adjust lash on 1, 3 and 5 exhaust and 1, 2 and 4 inlet valves.2. Turn adjusting screw counterclockwise 2 clicks or more to provide clearance between rocker assembly and valve.3. Turn adjusting screw clockwise to obtain zero lash. There should be no free rocker movement or adjusting screw button lateral movement. The adjusting screw button can still be rotated by finger pressure even when it is in contact with valve stem and clearance is zero. Turning the adjusting screw clockwise beyond this point will force the valve off its seat, and final lash setting will be incorrect.4. To adjust, turn adjustment screw counterclockwise 10 clicks (.020") (0.51 mm) for the exhaust valves and 4 clicks (.008") (0.20 mm) for the inlet valves. (One click is equal to .002") (0.05 mm).5. Turn crankshaft 360° clockwise, (direction of normal rotation) viewing from front. Align flywheel timing mark with timing pointer. a) Adjust 2, 4 and 6 exhaust